Tissue cutting device and system

ABSTRACT

The present disclosure relates to a tissue cutting system for cutting tissue of a heart, such as tissue of a septum of a heart, comprising: an outer tubular member having a proximal portion and a distal portion, said distal portion comprising a tissue resection window; a resection element axially slidably arranged inside the outer tubular member configured to resect tissue extending through the tissue resection window; at least one pressure sensor; wherein the outer tubular member and resection element are arranged to establish: a first fluid flow channel suitable for transporting resected tissue away from an area adjacent to the resection element; at least one second fluid flow channel configured to assist the first fluid flow channel in transporting resected tissue. The present disclosure further relates to a method for resecting tissue using the disclosed tissue cutting system.

The present disclosure relates to a tissue cutting device, a tissuecutting system and to a method for resecting tissue.

BACKGROUND OF INVENTION

Heart disease is the most common chronic disease in the developed world,and quickly increasing the developing world. It is responsible of 16% ofthe deaths in high income countries and 14% in middle income countriesas defined by the World Health Organization. Ischemic heart disease isthe most common for mortality, with valvular disease in the secondplace. Between 2% and 4% of the population over 65 is estimated to havesome type of valvular disease. The most common valvular disease is theaortic stenosis, followed by mitral stenosis and mitral regurgitation.Another condition that is not uncommon is subvalvular stenosis due tohypertrophy of the septum (106), where there is an obstruction below theaortic valve that affect the heart in the same way as the aorticstenosis does (FIGS. 1a and b ). Subvalvular stenosis increases the workneeded for the heart to maintain the blood pressure and cardiac output.When severe, the condition decreases cardiac output with decreasedphysical strength as a consequence. In addition, the condition increasesthe likelihood of dying prematurely in heart failure.

Septal hypertrophy is the medical term used when the septum dividing theright and left ventricle of the heart is hypertrophic, i.e. thicker thannormally. This thickening will lead to an obstruction in the outflow ofthe left ventricle. The pathogenesis of septal hypertrophy is mainlytwofold. First it could be a part of a hypertrophic cardiomyopathy,where the entire muscle mass of the heart is increased. The second causeis secondary to an aortic stenosis, where the stenosis of the valveleads to an increase in work load and increase in the muscle mass of theseptum. In both these conditions, the thickness of the septum (106)increases from a normal 6-10 mm to up to 25-30 mm. The thickest part isjust below in the aortic valve in the tubular part of the left ventricle(103) called the outflow tract (104) (FIG. 1b ). As the septum (106)bulges into this tubular part, an obstruction will develop in the partwhere the blood normally is ejected to the circulation.

Currently, the treatment modalities available for septal hypertrophyare 1) surgical myectomi, 2) Alcohol Septal Ablataion (ASA) and 3) dualchamber pace-maker pacing.

Surgical myectomi is done by routine open heart surgery, where the chestis opened by a median sternotomy, the patient is put on heart-lungmachine and the heart is arrested. When cardiopulmonary bypass isinstituted, the surgeon can open the heart and resect a part of thehypertrophic septum. Alcohol septal ablation is performed by instillingalcohol in the coronary arteries that supplies the septum with blood.The procedure is performed in a catheter lab with the patient awake, andthrough routine access in the groin. The alcohol will trigger a celldeath and necrosis, and thereby decreasing the volume of the septum.Pace-maker therapy is performed to achieve a contraction pattern of theseptum that will decrease the outflow obstruction.

All of the above treatment modalities are associated withinconveniences. Surgical myectomi is invasive and can be considered arelatively complicated surgical process involving substantial risks forthe patent undergoing the surgery since the chest has to be opened andthe heart arrested. ASA and pace-maker therapy can be considered to beselective alternatives for certain cases of e.g. lighter forms of septalhypertrophy in cases where surgical myectomi is not suitable for thepatient. The above described techniques for treating septal hypertrophyboth have the same disadvantage in that it is difficult to control theamount of septum to remove. Surgical resection depends on the experienceof the surgeon to remove the right amount of tissue. If the surgeonremoves too much tissue there will be a defect in the septum, in if thesurgeon removes too little the patient will not be entirely cured. ForASA the achieved effect is difficult to control as the operator does notknow how much of the septum that will go into necrosis.

SUMMARY OF INVENTION

Heart surgery without arresting the heart, in particular involvingresection of a part of the hypertrophic septum, presents severalchallenges that are not overcome by traditional tissue cutting devices.First of all, when performing surgery on a beating heart, the interiorof the heart is filled with blood, i.e. the surgery (tissue cutting) isperformed in the blood circulation. It is of importance thatsubstantially no blood should be aspirated from the heart or bloodcirculation during the surgery, nor should substantially no fluids beadded to the blood circulation from the device or anything belonging tothe system of the device.

Furthermore, when working on a beating heart, the pressure in the bloodin the heart chambers varies, both within one cardiac cycle and overseveral cardiac cycles, which varies the relative pressure between atransportation channel of a tissue cutting device and the externalenvironment in which it operates accordingly.

Yet another issue when performing surgery in the blood circulation, ascompared to other organs of the body, is that no resected tissue shouldbe allowed to be released into the blood circulation in order to avoidembolic events, thrombosis or the like.

The present disclosure relates to a tissue cutting system for cuttingtissue of a heart, such as tissue of a septum of a heart, comprising: anouter tubular member having a proximal portion and a distal portion,said distal portion comprising a tissue resection window; a resectionelement axially slidably arranged inside the outer tubular memberconfigured to resect tissue extending through the tissue resectionwindow; at least one pressure sensor; wherein the outer tubular memberand resection element are arranged to establish: a first fluid flowchannel suitable for transporting resected tissue away from an areaadjacent to the resection element; at least one second fluid flowchannel configured to assist the first fluid flow channel intransporting resected tissue.

A tissue cutting system according to the present invention can be seenas a tool to resect tissue in a controlled manner with reducedinvasiveness. This can be achieved by a device having an outer tubularmember and an internal cutting mechanism which is slidably arrangedinside the outer tubular member. To cut and remove tissue the device isheld close to the tissue to be resected, while the resection window isopen. By aspirating through the first fluid flow channel, tissue isaspirated through the resection window, thereby extending through thetissue resection window. While the tissue extends through the resectionwindow, the resection element can be moved across the resection windowalong the axis of the outer tubular outer member to resect the tissueextending through the resection window. Once the tissue is resected itcan be transported away from the resection element through the firstfluid flow channel. In addition to the first fluid flow channel there isat least one second fluid flow channel. The at least one second fluidflow channel is typically but not necessarily located between the outertubular member and inner tubular member. The second fluid flow channelcan generally be said to regulate a pressure in the tissue cuttingdevice, and more specifically in the distal portion. In one embodimentthe step of regulating a pressure comprises the step of maintainingequilibrium in relation to the pressure outside the device when theresection window is open. In one embodiment the step of regulating apressure comprises the step of increasing the pressure in the secondfluid flow channel, thereby applying liquid to a region adjacent to theresection window, where tissue is cut, thereby assisting the first fluidflow channel in transporting resected tissue away from the resectionelement.

The present invention may further comprise any of the followingfeatures: a vacuum generator; a collector for collecting the resectedtissue; an actuator for controlling a sliding movement of the resectionelement along the outer tubular member; and a housing. In one embodimentthe tissue cutting system is a complete system for removing tissue. Inone embodiment, the tissue cutting system is configured to resect ahypertrophic septum of a heart, and therefore, accordingly, the tissuecutting system is a device suitable for resecting and removing tissue ofa hypertrophic septum of a heart.

A further aspect of the presently disclosed invention relates to amethod for resecting tissue using a tissue cutting system as describedabove. The method presents a major advantage compared to for examplesurgical myectomi in that the method is considerably less invasive. Inone embodiment the method also gives a continuous monitoring of how muchtissue has been resected, giving the operator feed-back as when tocontinue or stop resecting. This can be achieved by continuousmonitoring by echocardiography of the heart (either as a transeosophagelechocardiography or transthoracic echocardiography). A continuousmonitoring of the systolic and diastolic pressure in the right ventriclethrough the instrument together with continuous monitoring of thearterial pressure will give a measure of the degree of outflowobstruction, and the treatment effect which can also be used to guidethe effectiveness of the procedure. The method comprises the steps of:positioning the resection window adjacent to tissue to cut; generating avacuum pressure; connecting the vacuum pressure to the first fluid flowchannel, thereby aspirating tissue through the resection window;measuring and analysing the pressure in the first fluid channel for apredefined period of time; and if the measured period remains below apredefined pressure threshold for longer than a predefine period oftime, sliding the resection element thereby cutting tissue, otherwisedisconnecting the vacuum pressure to the first fluid flow channel. Thesteps may be iteratively repeated. The presently disclosed tissuecutting system provides a possibility to cut tissue in a heart whilepreventing unnecessary aspiration of blood from the heart. When thevacuum pressure is connected, e.g. by opening a valve, it will quicklybe realized whether the resection window is filled with tissue withoutleakage. If the pressure remains low for a predefined period of time, itis considered that the device has been positioned such that the vacuumis able to “grip” the tissue without leakage and the cutting can bedone. If the pressure in the first fluid flow channel remains low onlytemporarily and then goes back to a higher level, it can be used as anindication that the generated the resection window has not “gripped” thetissue and the vacuum pressure must therefore be disconnected in orderto avoid aspiration of blood.

Alternatively the method comprises the steps of: opening the tissueresection window and during and after the opening regulating thepressure in the distal portion through the at least one second fluidflow channel such that the pressure is substantially equal to thepressure outside the tissue cutting system; activate a vacuum generatorconnected to the first fluid flow channel such that tissue locatedoutside the cutting system is aspirated into the distal portion of theouter tubular member through the tissue resection window; closing thetissue resection window by sliding the inner tubular member in an axialdirection lengthwise of the outer tubular member towards the closeddistal end, the resection element thereby resecting tissue extendingthrough the tissue resection window; increasing the pressure in theouter channel to generate a flow of liquid through the outer channeltowards the distal portion, the flow of liquid continuing from thedistal portion away from the distal portion through the first fluid flowchannel. The inventor has realized that by using a second fluid flowchannel to balance the pressure in the distal portion adjacent to theresection window with a pressure outside the device the device can usedinvasively since the equilibrium in relation to the pressure outside thedevice prevents that material moves between the outside and the insideof the device. Before the vacuum generator is activated in the secondstep, the resection window should preferably be located adjacent to ordirectly against the tissue to be resected. The vacuum generator is thenactivated, preferably decreasing the pressure in the cutting devicerapidly, and tissue is aspirated into the distal portion of the outertubular member through the tissue resection window. The inner tubularmember is then slid inside the outer tubular member, thereby closing theresection window and cutting tissue. At approximately the same time orslightly after the pressure in the second fluid flow channel isincreased to generate a flow of liquid through the outer channel towardsthe distal portion, thereby assisting in transporting tissue away fromthe cutting element.

These and other aspects of the invention are set forth in the followingdetailed description if the invention.

DESCRIPTION OF DRAWINGS

The invention will in the following be described in greater detail withreference to the accompanying drawings. The drawings are exemplary andare intended to illustrate some of the features of the presentlydisclosed tissue cutting system, and are not to be construed as limitingto the presently disclosed invention.

FIG. 1a-b show two versions of a transection of a heart. FIG. 1a shows atransection of a normal heart. FIG. 1b shows a transection of a hearthaving a hypertrophic septum.

FIG. 2a-b show two versions of a transverse section of a porcine heart.FIG. 2a shows an untreated heart and FIG. 2b shows a heart where tissuehas been removed from the septal part.

FIG. 3a-b show an embodiment of the tissue cutting system. In FIG. 3athe resection window is closed and in FIG. 3b the resection window isopen.

FIG. 4a-b show another embodiment of the tissue cutting system. Thefigures illustrate how tissue is aspirated into the distal portion ofthe device and transported away from the resection element through thefirst fluid flow channel.

FIG. 5 shows an embodiment of the tissue cutting system, wherein theouter tubular member has a plug at the distal end.

FIG. 6 shows a selection of outer tubular members made in one piece.

FIG. 7a-c show three different resection elements.

FIG. 8 shows an embodiment of a tissue cutting device according to thepresent invention.

FIG. 9 shows another embodiment of a tissue cutting device according tothe present invention.

FIG. 10 shows a mechanical solution of the tissue cutting device,configured to control the inner tubular member.

FIG. 11 shows a part of one embodiment of the tissue cutting device,comprising a collet to stabilize the movement of the inner tubularmember and to seal the flow of liquid within the intended premises.

FIG. 12 shows one embodiment of the tissue cutting system having acatheter and a control device.

FIG. 13 shows a cross-section of one embodiment of the tissue cuttingsystem having first and second fluid flow channels, further comprising athird resection element control channel, a fourth guidewire channel anda fifth flex channel.

FIG. 14 shows a further embodiment of the tissue cutting system having abackwardly cutting resection element.

FIG. 15a-b show examples of usage of the tissue cutting system.

FIG. 16 shows a pressure diagram for an operating scenario of the tissuecutting system.

FIG. 17 shows a system for controlling and monitoring the operation ofthe tissue cutting system.

DETAILED DESCRIPTION OF THE INVENTION

The present disclosure relates to a tissue cutting system for cuttingtissue of a heart, such as tissue of a septum of a heart, comprising: anouter tubular member having a proximal portion and a distal portion,said distal portion comprising a tissue resection window; a resectionelement axially slidably arranged inside the outer tubular memberconfigured to resect tissue extending through the tissue resectionwindow, and at least one pressure sensor wherein the outer tubularmember and the resection element are arranged to establish: a firstfluid flow channel suitable for transporting resected tissue away froman area adjacent to the resection element; at least one second fluidflow channel configured to assist the first fluid flow channel intransporting resected tissue. The device may be a transcatheter devicedesigned to resect tissue, such as parts of the septum, in a controlledmanner with a minimal invasive approach.

The system may further comprise an inner tubular member axially slidablyarranged inside the outer tubular member. The outer and inner tubularmembers are preferably rigid. The inner tubular member being axiallyslidably arranged inside the outer tubular member means that it can bemoved in the longitudinal direction of the outer tubular member. FIGS.3a and b show one embodiment of the device, in which the inner tubularmember (203) is located at different positions in relation to the outertubular member (201). The outer tubular member having a resection windowrefers to an opening through which tissue can extend, typically by meansof aspiration. The distal portion of the outer tubular member refers tothe part of the tubular member being location adjacent to the resectionwindow and the proximal accordingly to the opposite part of the outertubular member. The device further comprises a resection elementconfigured to resect tissue extending through the tissue resectionwindow. This means that the resection element is configured to slideacross the resection window parallel to the sidewall of the outertubular member to shear tissue that is located inside the outer tubularmember. Typically the resection element is an integrated part of theinner tubular member.

‘Tubular’ in inner and outer tubular members is to be construed broadlyand includes pipes and cylinders having any suitable cross-section thatis substantially circular, oval, rounded, square, rectangular or othershape, which would be known to those skilled in the art.

The inner and outer tubular members are arranged to establish a firstfluid flow channel suitable for transporting resected tissue away froman area adjacent to the resection element, and at least one second fluidflow channel suitable for regulating a pressure in the distal portionand/or configured to assist the first fluid flow channel in transportingresected tissue. This design allows that the device is connected to avacuum generator (more specifically that the first fluid flow channel,which may be the interior of the inner tubular member, is connected to avacuum generator), and when the vacuum generator is activated theresected tissue is aspirated away from the area in the distal portion ofthe outer tubular member adjacent to the resection window. ‘Vacuum’ maygenerally be referred to a pressure much less than atmospheric pressure.In relation to the present invention, ‘vacuum’ is construed broadly asan at least partial vacuum (imperfect vacuum) with the intention that apressure in the first fluid flow channel that is negative in relation tothe pressure outside the resection window can be used to aspirate tissueinto the first fluid flow channel, and, after being cut, further throughthe first fluid flow channel. The at least one second fluid flow channelmay have different purposes, which can broadly be described asregulating a pressure in the distal portion and/or assisting the firstfluid flow channel in transporting resected tissue. More specificallythis means that when the resection window is open, the outside of thedevice and the inside of the device is in fluid connection. To preventthat material moves from the outside to the inside or vice versa thesecond fluid flow channel can regulate the pressure such thatequilibrium is maintained, i.e. the pressure is substantially the sameinside and outside the device. When the resection window is closed thesecond fluid flow channel can be used to assist the first fluid channelin transporting resected tissue away from the distal part through thefirst fluid channel. This may be achieved by increasing the pressure ofa liquid connected to the second fluid flow channel. As a consequence,the liquid flows through the second fluid flow channel towards thedistal portion of the device, where resected tissue is flushes awaythrough the first fluid flow channel.

Resection Window

The resection device of the tissue cutting system may have differentdimensions, location and design depending on the tissue to cut, thedimensions of the inner and outer tubular members, the performance of avacuum generator connected to the device etc.

When used invasively there may be physical constraints that have to betaken into account. One such constraint is related to the limited spacearound the septum of a heart. Therefore, one aspect of the presentlydisclosed tissue cutting device relates to the resection window beinglocated sufficiently close to a closed distal end of the outer tubularmember that the device can be positioned close to the tissue to beresected without damaging other surrounding parts. Therefore, theresection window may be located proximate to a closed distal end of theouter tubular member, such as less than 0.1 mm, or less than 0.2 mm, orless than 0.3 mm, or less than 0.4 mm, or less than 0.5 mm, or less than1.0 mm, or less than 2.0 mm, or less than 3.0 mm, or less than 4.0 mm,or less than 5.0 mm, or less than 10 mm, or less than 15 mm, or lessthan 20 mm, or less than 25 mm, or less than 30 mm.

As stated, the dimensions and the shape of the resection window dependon a number of factors. The resection window may have a length of lessthan 3 mm, or less than 4 mm, or less than 5 mm, or less than 6 mm, orless than 7 mm, or less than 8 mm, or less than 9 mm, or less than 10mm, or less than 15 mm, or less than 20 mm, or less than 25 mm, or lessthan 30 mm, or less than 50 mm. Length is defined as the distance of theresection window in the longitudinal direction of the outer tubularmember. If the device is used to resect the hypertrophic septum of aheart, the size of the window preferably has a size that supports a safeand secure resection of small tissue parts. It will in most situationsbe preferred that septum resection is performed through several cuts,optionally in a session supported by e.g. transoesophageal ortransthoracic echocardiography of the heart and/or fluoroscopy, whereintissue parts are resected and removed repeatedly while the result (i.e.the size and shape of the septum after removal of tissue) iscontinuously checked. On the other hand, the larger pieces of tissuethat can be resected per cut, the faster the process. Hence, the lengthof the window is a trade-off between precision/granularity andspeed/efficiency.

Further different shapes of the resection are possible. Preferably thecurvature of the edge of the resection window is substantially smooth,and may have a substantially oval shape. If the cross-section of theouter tubular member is rounded or substantially circular, the resectionwindow typically extends over of portion of a circumference of the outertubular member. The resection window may extend over a portion of acircumference of the outer tubular member, such as less than 5% of thecircumference, or less than 6% of the circumference, or less than 7% ofthe circumference, or less than 8% of the circumference, or less than 9%of the circumference, or less than 10% of the circumference, or lessthan 15% of the circumference, or less than 20% of the circumference, orless than 30% of the circumference, or less than 40% of thecircumference, or less than 50% of the circumference, or less than 60%of the circumference.

One embodiment of the presently disclosed invention relates to theresection window having an edge sloping downwards towards the center ofthe resection window. An example of a resection window (202) having asloping edge (208) can be seen in FIG. 3a-b . Such a sloping edge can besaid to correspond to one of the blades of a pair of scissors. This is acommon design of the cutting edges of scissors. The edge of theresection window can be said to correspond to one of the blades of apair of scissors in this regard. The other blade corresponds to theresection element of the present invention. When the resection element(204), which is an integral part of inner tubular member (203) in thetissue cutting device in FIG. 3a-b , slides across the resection window,tissue (209) extending through the resection window is resected, asillustrated in FIG. 4a -b.

Resection Element

The resection element according to the present invention can takedifferent forms. The functionality can generally be said to be similarto that of scissors, i.e. two parallel blades sliding and when the edgesmeet the material that is between the two edges is sheared. In thepresent invention the resection element can be said to correspond to oneof the blades of a pair of scissors (the other blade corresponding tothe edge of the resection window, as explained above). However, thisillustration shall not be seen as limiting in the sense that theresection does not have to be a flat surface as the blade of scissors.

In one embodiment the resection element is configured to cut tissuebackwards towards a direction from the distal portion towards theproximal portion. This may be achieved by having the resection elementlocated distally to the resection window when the resection window isopen. FIG. 14 shows such an implementation. The resection element may bedirectly connected to or forming an integral part of a plunger sealinglyengaged inside the outer tubular member, as shown in FIG. 14. Theplunger and outer tubular member may form a chamber which can be used topush or retract the resection element by regulating the pressure insidethe chamber. This embodiment is particularly useful if the tissuecutting device is connected through for example a plastic catheter sinceit enables a possibility to control the resection element through afluidly connected element by regulating for example the pressure of afluid rather than a rigidly connected mechanism.

In relation to such an embodiment a resection element control channelmay be incorporated into the sidewall of the outer tubular member,wherein the resection element control channel is in fluid connectionwith a closed chamber defined by the outer tubular member and theplunger. The system may be configured to control a fluid in the closedchamber such that when a chamber pressure in the chamber is increased abackwards movement of the resection element is produced and when thechamber pressure is decreased a forwards movement of the resectionelement is produced.

Further options for controlling the resection element may include theuse of a wire and/or a substantially rigid mechanical connection betweenthe control device and the resection element. The connection between thecontrol device and the resection element may be driven by a motor, forexample an electrical motor.

In one embodiment, the resection element is an integrated part of theinner tubular member. Therefore, in one embodiment of the invention theinner tubular member has a hollow interior defining the first fluid flowchannel extending from an open proximal end of the inner tubular memberto an open distal end of the inner tubular member, said open distal endcomprising a cutting surface defining an acute angle to the longitudinalaxis of the inner tubular member, forming a substantially oval edge ofthe inner tubular member. Examples of such embodiments are shown in FIG.7-a-c. The open distal end shall in this context be construed as the endwhich is located adjacent to the distal portion of the outer tubularmember, i.e. where the resection window is located. The open proximalend shall be construed as the opposite end of the inner tubular member,possibly configured to be connected to a vacuum generator.Alternatively, the inner tubular member can be said to be a tissuepenetrating cannula, wherein the open distal end is sharp.

From the above explanations it can be noted that the resection elementmay be either substantially flat, or, if it is regarded as an extensionof the inner tubular member, having a substantially round cross-sectionfollowing the contour of the inside of the outer tubular member. Besidesresecting tissue extending through the resection window, the resectionelement should preferably be able to seal the resection window when ithas been slid across the resection window, i.e. act as a barrier betweenthe inside and the outside of the device such that no material can flowbetween the inside and the outside. In one embodiment, an upper side ofthe resection element is configured to slide smoothly along the insideof the outer tubular member, thereby cutting tissue extending throughthe tissue resection window. This design seals the resection windowefficiently.

Different shapes of the resection elements are possible both in terms ofthe cutting edge of the inner tubular member (if the resection elementis an integral part of the inner tubular member) and the acute angle.FIG. 7a-c show a number of examples of shapes. In one embodiment thecannula is a lancet cannula having a sharpened front, and in oneembodiment the acute angle is between 1° and 30° and in anotherembodiment the open distal end of the inner tubular member comprises ascalpel or razor blade.

Configuration of Outer and Inner Tubular Members, and Fluid FlowChannels

As stated the tissue cutting system has an outer tubular member with aresection window, optionally an inner tubular member, and a resectionelement configured to resect tissue extending through the tissueresection window. The tubular members are arranged to establish a firstfluid flow channel and at least one second fluid flow channel.

In one embodiment the first fluid channel is defined as the hollowinterior of the inner tubular member. The at least one second fluid flowchannel can be a space between the outer tubular member and the innertubular member. In FIG. 3a , showing one embodiment of the presentlydisclosed invention, it can be seen that the upper side of the innertubular is located directly against the inside of the outer tubularmember (201). Upper side in this context shall be construed as the sideof tube closest to the resection window (202). In this embodiment thesecond fluid flow channel (206) is located in the opposite side of across-section of the outer tubular member in relation to the resectionwindow (202). The first fluid flow channel (205) is the hollow interiorof the inner tubular member (203) in this example. The second fluid flowchannel (206) in FIG. 3a is located in the lower section of the outertubular member (201), between the inner tubular member (203) and theouter tubular member (201). FIG. 4b shows a similar configuration, whichillustrates how resected tissue (209) is transported away from the areaadjacent to the resection element (204) through the first fluid flowchannel (205).

The at least one second fluid flow channel does not necessarily have tobe located between the outer tubular member and the inner tubularmember. If any of the sidewalls of the tubular members are sufficientlythick, the at least one second fluid flow channel may be incorporatedinto the sidewalls of the tubular members. Alternatively, in oneembodiment the cutting device has one or more additional fluid flowchannels on the outside of the device, either attached on the outside ofthe device or as separate channels. A consequence of such aconfiguration is that the device further comprises at least oneadditional tubular member outside the outer tubular member. Possibly,the device also comprises an additional tubular member inside the innertubular member.

In one embodiment, the cutting device has a device outer diameterbetween 2 mm and 20 mm, or between 2 mm and 15 mm, or between 2 mm and10 mm, or between 5 mm and 10 mm, or between 5 mm and 15 mm, such as 2mm, or 3 mm, or 4 mm, or 5 mm, or 6 mm, or 7 mm, or 8 mm, or 9 mm, or 10mm, or 11 mm, or 12 mm, or 13 mm, or 14 mm, or 15 mm, or 16 mm, or 17mm, or 18 mm, or 19 mm, or 20 mm. When used as a device for resectingthe hypertrophic septum of a human or animal heart, this outer diameterensures that the device is sufficiently small to be inserted into thebody through the apex of the heart via an intercostal space or throughthe vasculature of the body, and at the same time sufficiently large tocut as large pieces of tissue as possible.

The inner tubular inner diameter can be said to define an upper limit ofthe pieces of tissue that can be transported (in the case where theinterior of the inner tubular member defines the first fluid channel).In one embodiment the inner tubular member has an inner tubular innerdiameter between 1 mm and 10 mm, or between 1 mm and 7 mm, or between 1mm and 5 mm, or between 1 mm and 3 mm, such as 1 mm, or 2 mm, or 3 mm,or 4 mm, or 5 mm, or 6 mm, or 7 mm, or 8 mm, or 9 mm, or 10 mm, or 12mm, or 14 mm, or 16 mm, or 18 mm, or 19 mm.

In the case where the at least one second fluid flow channel is a spacebetween the outer tubular member and the inner tubular member, thedifference between an inner tubular outer diameter of the inner tubularmember and an outer tubular inner diameter can be said to define thewidth of the second fluid flow channel. The difference between an innertubular outer diameter of the inner tubular member and an outer tubularinner diameter can be less than 5 mm, or less than 4 mm, or less than 3mm, or less than 2 mm, or less than 1 mm, or less than 0.5 mm, or lessthan 0.4 mm, or less than 0.3 mm, or less than 0.2 mm, or less than 0.1mm.

The length of the device can be seen as the distance between the distalend and the proximal end of the outer tubular. The lower limit of thedevice is preferably such that the device extends from the point whereit operates, typically adjacent to the hypertrophic septum of a heart,to the outside of an area of critical tissue, organ or any other bodyfunction, e.g. beyond the apex of the heart. In one embodiment thetissue cutting device has a length of less than 30 mm, or less than 40mm, or less than 50 mm, or less than 60 mm, or less than 70 mm, or lessthan 80 mm, or less than 90 mm, or less than 100 mm. There is no upperlimit of this length—the device can in principle operate both as a shortdevice and a long device. Nevertheless, in one embodiment the tissuecutting device has a length of between 50 mm and 500 mm, or between 50mm and 400 mm, or between 100 mm and 300 mm, or between 50 mm and 200mm, or between 100 mm and 200 mm, or greater than 200 mm.

In another embodiment of the invention the cutting device is configuredfor use through the femoral artery, the ascending aorta, subclavianartery or any other great vessel of the body. Great vessels is a termused to refer collectively to the large vessels that bring blood to andfrom the heart, including the venae cavae, pulmonary artery, pulmonaryveins and aorta, and can in relation to the present invention beconstrued as any vessel through which the cutting device can pass. Inthis embodiment the tissue cutting device preferably further comprises aflexible section attached to the device configured to pass through anygreat vessel of the body, including for instance the aortic arch. In oneembodiment the flexible section has a length of between 50 mm and 1000mm, or between 50 mm and 500 mm, or between 100 mm and 300 mm, orbetween 50 mm and 200 mm, or between 100 mm and 200 mm, or greater than200 mm, such as 50 mm, or 60 mm, or 70 mm, or 80 mm, or 90 mm, or 100mm, or 150 mm, or 200 mm, or 300 mm, or 400 mm, or 500 mm, or 600 mm, or700 mm, or 800 mm, or 900 mm, or 1000 mm.

In one embodiment the tissue cutting device further comprises aguidewire to guide the tissue cutting device to a position inside thebody. A guidewire is a usually flexible wire that can be inserted to aspace to act as a guide for subsequent insertion of a stiffer or bulkierinstrument. Cardiovascular interventional guidewires are known to thoseskilled in the art. The guidewire is placed in one of the channels ofthe cutting device and can track its way to the correct position for thedevice to operate. Typically the guidewire is introduced before the restof the device through the access site (e.g. apex, femoral artery,ascending aorta, subclavian etc.). In one embodiment the tissue cuttingsystem further comprises a guidewire channel incorporated into thesidewall of the outer tubular member. A guidewire incorporated in thismanner may be useful for example if the tool is to be used by accessingthe heart transfemorally. In one embodiment the system therefore furthercomprises a guidewire arranged inside the guidewire channel extendingfrom a proximal end of the outer tubal member to a distal end of theouter tubular member.

In another embodiment the tissue cutting device further comprises anintroducer configured to introduce the tissue cutting device into anypart or organ of the body, such as the heart. Introducers are known inthe art and are used to provide access to the heart. Introducers maycomprise means for puncturing tissue and means for providing access tothe interior of the heart.

Preferably, the tissue cutting device is made of a rigid materialselected from the group of ceramics, ceramic composites, metal, such asaluminium or steel, or plastics, such as polycarbonate (PC) orpolymethylmethacrylate (PMMA).

Functional Description

As stated, the fluid flow channels of the present invention areconfigured to perform different functional tasks; the first fluid flowchannel is suitable for transporting resected tissue away from an areaadjacent to the resection element, and the at least one second fluidflow channel is/are suitable for regulating a pressure in the distalportion and/or assist the first fluid flow channel in transportingresected tissue. More specifically, the first fluid flow does nottransport the resected tissue by itself but typically by a deviceaspirating the tissue through the channel. Therefore, in one embodimentthe first fluid flow channel is configured to be connected to a vacuumsource configured to establish a fluid flow to aspirate resected tissueaway from an area adjacent to the resection element through the channel.This typically happens when the resection element has been slid forward,thereby resecting tissue extending through the resection window, suchthat there are loose tissue parts in the distal portion of the outertubular member. Typically, the tissue is transported away from theresection element by means of aspiration. The term vacuum generatorshall be construed broadly as any device capable of generating anegative pressure in relation to a given starting point pressure. Vacuumin this sense does not necessarily mean absolute vacuum, but includespartial vacuum, i.e. any negative pressure between the original pressureand absolute vacuum.

In one embodiment, which may be a transfemoral embodiment of the tissuecutting system, a flexible catheter is connected to the outer tubularmember. In one embodiment the system also comprises a control device forcontrolling the resection device and/or other functions of the system.One example of a control device is shown in FIG. 12. The control devicemay be configured to control a number of functions e.g. the vacuumgenerator and/or application of the vacuum generator and/or applicationof fluid into the second fluid flow channel.

In order to improve the placement of the resection window, the inventorhas also realized that in the narrow and challenging space where thecutting device operates it may be useful to be able to flex or bend theouter tubular member slightly to reach a part of tissue to be aspiratedand cut. In one embodiment the tissue cutting system therefore furthercomprises a flex channel incorporated into the sidewall of the outertubular member. A control device may be configured to control a flexwire in the flex channel for example such that when the wire istightened it will cause a part of the outer tubular member to flex orbend slightly.

The at least one second fluid flow channel is/are suitable forregulating a pressure in the distal portion and/or assist the firstfluid flow channel in transporting resected tissue. In a first aspectregulating a pressure in the distal portion may have the meaning thatthe pressure in the distal portion shall be maintained at substantiallythe same level as the pressure outside the device. This has theadvantage that if the tool is used for surgery, for example resectingthe hypertrophic septum of a heart, maintaining pressure inside thedevice substantially equal to the pressure outside prevents thatmaterial moves from the inside of the device out to the body and viceversa when the resection window is open. Therefore, in one embodiment ofthe present invention the at least one second fluid flow channel issuitable for regulating a pressure in the distal portion such thatmaterial does not flow between an outer area of the device and an innerarea when the resection window is open.

Therefore, in one embodiment the device further comprises at least onepressure sensor. In a further embodiment, one sensor is located outsidethe device and one pressure sensor inside the device. The inside sensormay be located in the distal portion or the proximate portion of theouter tubular member, or in the distal end or proximal end of the innertubular member, and the outside sensor may be located outside the outertubular member. In one embodiment the pressure(s) is/are measured inreal-time. Preferably the pressure in the distal portion is alsoregulated real-time by means of a pressure regulator connected to thesecond fluid flow channel. As stated above, the arterial pressure variesboth within one cardiac cycle and over several cardiac cycles. As aconsequence, the relative pressure between the distal portion or theproximate portion of the outer tubular member and an area outside thedevice, e.g. in the aorta or left ventricle, also varies. The presentlydisclosed tissue cutting device, having at least one pressure sensor,can be used in heart surgery without arresting the heart, in particularinvolving resection of a part of the hypertrophic septum. Bycompensating a difference in pressure between the outside and inside ofthe device based on data from the sensors, it can be prevented thatliquid enters or leaves the device involuntarily and that resectedtissue is released in the blood circulation. In one embodiment theoutside pressure is calculated as an average pressure value over acardiac cycle.

In one embodiment of the present invention, the at least one secondfluid flow channel is configured to assist the first fluid flow channelin transporting resected tissue away from the resection element throughthe first fluid flow channel when the resection window is closed. Thisis achieved by increasing the pressure in the second fluid flow channelwhen the resection window is closed. The first fluid flow channel andthe second fluid flow channel can then be seen as a closed system ofchannels. If the second fluid flow channels contains a liquid, such aswater, or a saline solution, or a glucose solution, to regulate thepressure, the liquid will flow from the second fluid flow channel to thefirst fluid flow channel. In one embodiment the at least one secondfluid flow channel is configured to flush resected tissue away from thedistal portion through the first fluid flow channel, wherein thepressure regulator is configured to generate a flow of liquid throughthe at least one second fluid flow channel towards the distal portion,the flow of liquid continuing from the distal portion away from thedistal portion through the first fluid flow channel.

The device may have more than one second fluid flow channel for severalreasons. One reason may be that the pressure can be regulated moreefficiently if there are several channels. For example, in aconfiguration where resected tissue is flushed away from an areaadjacent to the resection element, the second fluid flow channel may belocated such that liquid flows from several directions towards theresected tissue. Another reason for having more than one second fluidflow channel is to separate the pressure regulating function when theresection window is open and the flushing function when the resectionwindow is closed. Therefore, in one embodiment a primary channel of theat least one second fluid flow channels is suitable for regulating apressure in the distal portion, and a secondary channel of the at leastone second fluid flow channels is configured to flush resected tissueaway from the distal portion through the first fluid flow channel.

The tissue cutting device may further comprise one or moretransmitter(s) and/or transducer(s) configured to indicate the locationof the tissue cutting device. In one embodiment, thetransmitter(s)/transducer(s) is/are ultrasonictransmitter(s)/transducer(s). The advantage of havingtransmitter(s)/transducer(s) on the device is that when the tool is usedfor surgery, for example resection of the hypertrophic septum of aheart, the tool is typically not directly visible to the surgeon. Sincethe positioning of the tool can be crucial, the transmitters constitutea means to track the location of the device in relation to the septalpart of the heart. The transmitter(s) may be located anywhere on thedevice. In a preferred embodiment, the transmitter(s) is/are located atthe closed distal end of the outer tubular member, either inside oroutside the device.

Application

The tissue cutting device according to the presently disclosed inventionis primarily a surgical instrument.

As stated, septal hypertrophy is the medical term used when the septumdividing the right and left ventricle of the heart is hypertrophic, i.e.thicker than normally. Surgical myectomi is done by routine open heartsurgery, where the chest is opened by a median sternotomy, the patientis put on heart-lung machine and the heart is arrested. The tissuecutting device according to the present invention is suitable for use asa surgical instrument configured to resect tissue of a human and/oranimal heart. More specifically, the device is suitable for resectingthe hypertrophic septum of a heart. In principle the device could alsobe used to cut other tissue, either with the intention of removingtissue or for sampling purposes (biopsy).

When used as a device for resecting the hypertrophic septum of a heart,the device is typically inserted in the heart through the apex of aheart or inserted through the vasculature of the body, such as thefemoral artery, ascending aorta or subclavian artery. Inserting thetissue cutting device for resection of the hypertrophic septum of aheart can be done as for any intra-arterial device and is known to thoseskilled in the art.

Method for Resecting Tissue

A further aspect of the presently disclosed invention relates to amethod for resecting tissue using the tissue cutting system according tothe present disclosure, comprising the steps of:

-   -   positioning the resection window adjacent to tissue to cut;    -   generating a vacuum pressure;    -   connecting the vacuum pressure to the first fluid flow channel,        thereby aspirating tissue through the resection window;    -   measuring and analysing the pressure in the first fluid channel        for a predefined period of time; and    -   if the measured period remains below a predefined pressure        threshold for longer than a predefine period of time, sliding        the resection element thereby cutting tissue, otherwise        disconnecting the vacuum pressure to the first fluid flow        channel.

By using the at least one pressure sensor of the tissue cutting systemit is possible to implement a method that is capable of cutting tissuewhile avoiding that substantially any blood is aspirated from the heartor blood circulation during the surgery. In the method, typically avacuum generator is initially activated. In principle, the vacuumgenerator is preferably enabled throughout the process. Quick generationof vacuum is typically generated by building up an external vacuum andthen connecting the generated vacuum to the first fluid flow channel. Ina typical process the resection window is therefore placed adjacent to,preferably directly on, the tissue to be resected. At some point thegenerated vacuum is connected to the first fluid flow channel, whichwill cause the pressure to fall rapidly and aspirate tissue through theresection window. The pressure is measured continuously in the firstfluid flow channel and possibly monitored or analyzed automatically. Ifthe pressure remains at a low level, i.e. below a predefined thresholdit corresponds to the tissue filling the whole resection window withoutany substantial leakage. If this is the case the resection element canbe controlled (slid) to cut the tissue extending through the tissueresection window. If, on the other hand, the pressure does not go belowthe predefined threshold or returns to a higher level, it shows thatthere is a leakage and there is a risk that blood is aspirated. In thiscase the vacuum should be disconnected.

Furthermore a method for resecting tissue using the tissue cuttingdevice as described, comprising the steps:

-   -   opening the tissue resection window and during and after the        opening regulating the pressure in the distal portion through        the at least one second fluid flow channel such that the        pressure is substantially equal to the pressure outside the        tissue cutting device;    -   activate a vacuum generator connected to the first fluid flow        channel such that tissue located outside the cutting device is        aspirated into the distal portion of the outer tubular member        through the tissue resection window;    -   closing the tissue resection window by sliding the inner tubular        member in an axial direction lengthwise of the outer tubular        member towards the closed distal end, the resection element        thereby resecting tissue extending through the tissue resection        window;    -   increasing the pressure in the outer channel to generate a flow        of liquid through the outer channel towards the distal portion,        the flow of liquid continuing from the distal portion away from        the distal portion through the first fluid flow channel.

FIG. 4a-b may serve as an illustration of the method. In FIG. 4a theresection window (202) is open. Hence, the first step, opening thetissue resection window, has already been done at this point. The stepof regulating the pressure in the distal portion through the at leastone second fluid flow channel such that the pressure is substantiallyequal to the pressure outside the tissue cutting device is not shown inFIG. 4a . In FIG. 4a , a vacuum generator connected to the first fluidflow channel has been activated to aspirate tissue (209) into the distalportion of the outer tubular member through the tissue resection window.It can be seen in FIG. 4a how tissue (209) extends through the resectionwindow. An arrow indicates that the inner tubular member (203) is aboutto slide to the left in the drawing, thereby closing the tissueresection window and resecting tissue extending through the tissueresection window. At approximately the same time as the same time as theresection window closes, the pressure in the second fluid flow channel(206) is increased to generate a flow of liquid through the outerchannel towards the distal portion, which is shown in FIG. 4b . FIG. 4bshows how a flow of liquid is generated from the second fluid flowchannel (206) towards the distal portion and further on to the firstfluid flow channel (205), thereby assisting in transporting the tissue(209) away from the distal portion through the first fluid flow channel(205).

The vacuum generator does not necessarily have to generate absolutevacuum. Vacuum in this sense does not mean absolute vacuum, but includespartial vacuum, i.e. any negative pressure between the original pressureand absolute vacuum. In a preferred embodiment the vacuum generator isconfigured to decrease the pressure in the inner tubular member rapidly.

Typical use involves repeating the steps of the method for resectingtissue. Therefore, a complete sequence of steps to resect and removetissue typically includes the step of positioning the device such thatthe resection window is located adjacent to or in direct contact withthe tissue to resect, executing the steps of the disclosed method forresecting tissue, resetting the pressure in the first and second fluidflow channels, repositioning the device adjacent to a new piece oftissue to resects, and so forth until the desired amount of tissue hasbeen removed.

Tissue Removal Device

The presently disclosed invention further relates to a tissue removaldevice comprising the tissue cutting device, the tissue removal devicefurther comprising: a vacuum generator; a collector for collecting theresected tissue; an actuator for controlling a sliding movement of theinner tubular member along the outer tubular member; and a housing. FIG.9 show an example of such a tissue removal device. The vacuum generator(305) is not shown explicitly but pointed; however its position in thesystem is indicated and its connection through a pipe to the first fluidchannel of the tissue cutting device (200).

The tissue removal device may include a lever mechanism configured forpushing the inner tubular member in an axial direction lengthwise of theouter tubular member towards the closed distal end, wherein the lever isconnected to the actuator. FIG. 10 shows an example of such a levermechanism.

In a preferred embodiment the tissue removal device further comprises aregulating system for regulating the pressure in the distal portion andregulating the secondary pressure in the first tubular member and distalportion controlled by the vacuum generator.

DETAILED DESCRIPTION OF THE DRAWINGS

FIG. 1a-b show two versions of a transection of a heart. FIG. 1a shows atransection of a normal heart. FIG. 1b shows a transection of a hearthaving a hypertrophic septum. When the aortic valve (101) opens, bloodgoes from the left ventricle (103) into the aorta (105). The outflowtract (104) of the left ventricle is a portion through which bloodpasses in order to enter the aorta (105). The mitral valve (102) is adual-flap valve between the left atrium and the left ventricle (103).The septum (106) between the left and right ventricle can be considerednormal in FIG. 1a and enlarged in FIG. 1b , thereby protruding into theoutflow tract (104) in the latter.

FIG. 2a-b show two versions of a transverse section of a porcine heart.FIG. 2a shows an untreated heart and FIG. 2b shows a heart where tissuehas been removed from the septal part. The drawings show the shapes andpositions of the left ventricle (103), the right ventricle (107), andthe septum (106). In FIG. 2b tissue has been removed from the septum(106).

FIG. 3a-b show an embodiment of the tissue cutting device (200). In FIG.3a the resection window (202) is closed and in FIG. 3b the resectionwindow (202) is open. The device has an outer tubular member (201) (witha distal portion (210)), a distal end (207), an inner tubular member(203) and a resection element (204). The tubular members form a firstfluid flow channel (205) and a second fluid flow channel (206). Theresection window (202) has a sloping edge (208).

FIG. 4a-b show another embodiment of the tissue cutting device (200).The figures illustrate how tissue (209) is aspirated (FIG. 4a ) into thedistal portion of the device and transported away (FIG. 4b ) from theresection element through the first fluid flow channel (205). The devicehas an outer tubular member (201) (with a distal portion (210)), aninner tubular member (203) and a resection element (204). The tubularmembers form a first fluid flow channel (205) and a second fluid flowchannel (206). The resection window (202) has a sloping edge (208).

FIG. 5 shows an embodiment of the tissue cutting device (202) having aresection window (202), wherein the outer tubular member (201) has aplug (210) at the distal end.

FIG. 6 shows a selection of outer tubular members made in one piece.

FIG. 7a-c show three different resection elements. In these examples,the resection elements are integrated parts of the inner tubular member(203), having cutting surfaces (211) of different shapes, such as ovalinside-oval outside (FIG. 7a ), pointed inside-pointed outside (FIG. 7b) and oval inside-pointed outside (FIG. 7c ).

FIG. 8 shows an embodiment of a tissue cutting system (300) according tothe present invention, having a tissue cutting device (200), a trigger(301), a lever (303) and a spring (302) for pushing the resectionelement backwards to open the resection window.

FIG. 9 shows another embodiment of a tissue cutting system (300)according to the present invention, having a tissue cutting device(200), a lever (303), a vacuum activator (304), a liquid inlet (308), ahousing (314), a manometer connection (307), a pinch valve (306). Thereis no vacuum source shown in the system; however 305 is an indication ofwhere a vacuum source would be connected.

FIG. 10 shows a mechanical solution of the tissue cutting system,configured to control the inner tubular member, including a lever (303),a spring (302), a trigger pivot (309), a trigger button (310) and atrigger release spring (311).

FIG. 11 shows a part of one embodiment of the tissue cutting system,comprising a collet (312) to stabilize the movement of the inner tubularmember (203) and to seal the flow of liquid within the intendedpremises. The tissue removal device has a luer connector liquid flow(308) and a quad-ring (313).

FIG. 12 shows one embodiment of the tissue cutting system having acatheter (318) connected between a tissue cutting device (200) and acontrol device (314). A guidewire (316) (having a guidewire tip 316)extends through the tissue cutting device (200) and the catheter (318).The length of the catheter may be adapted to e.g. transfemoral use ofthe system for cutting tissue of a heart. The control device (314)comprises flex control (319) for flexing of cutting device (200), acutting control handle (304), a flush fluid port (324), pressure controlport (325) for controlling the resection element, a vacuum port (320),and a release button (322) for applying a generated vacuum to the firstfluid flow channel.

FIG. 13 shows a cross-section of one embodiment of the tissue cuttingsystem (200) having first (205) and second (206) fluid flow channels,further comprising a third resection element control channel (212), afourth guidewire channel (213) and a fifth flex channel (214).

FIG. 14 shows a further embodiment of the tissue cutting system (200)having a backwardly cutting resection element (204). A plunger (216) andthe outer tubular member (201) define a chamber (215) which can be usedto push or retract the plunger (216) by regulating the pressure insidethe chamber through the resection element control channel (212). Theouter tubular member (201) also form a first fluid flow channel (205)configured to transport tissue away from a region adjacent to theresection window (202). In the example the second fluid flow channel(206) is incorporated in the sidewall of the outer tubular member.

FIG. 15a-b show examples of usage of the tissue cutting system (300). InFIG. 15a the device is inserted through the apex (108) and in FIG. 15bthe device is inserted through the aorta (105).

FIG. 16 shows a pressure diagram for an operating scenario of the tissuecutting system. It can be noted that the pressure, shown as a functionof time, is inverted, which means that a higher value corresponds to alower pressure. The displayed scenario involves five attempts to apply agenerated vacuum to a region adjacent to the resection window of theinstrument. Four of the attempts to aspirate tissue without leakage aresuccessful (401), which corresponds to that the pressure drops quicklywhen the vacuum is applied and stays low for a predefined amount of timeuntil tissue is cut and the resection window is closed again. Peak 402corresponds to an attempt wherein there is leakage or the resectionwindow does not attach to the tissue to be resected when vacuum isapplied. In this case the pressure drops quickly but does not remain ona low level. In this case the attempt is preferably interrupted and theresection window closed in order not to aspirate blood from the heart.

When the vacuum pressure is connected, e.g. by opening a valve, it willquickly be realized whether the resection window is filled with tissuewithout leakage

FIG. 17 shows a system for controlling and monitoring the operation ofthe tissue cutting system (300). The pressure is measured and connectedto monitoring means (321). Based on the measured pressure, the systemcan then, manually or automatically, control a vacuum generator (323)and a valve (306).

FURTHER DETAILS OF THE INVENTION

-   -   1. A tissue cutting device comprising:        -   an outer tubular member having a proximal portion and a            distal portion, said distal portion comprising a tissue            resection window;        -   an inner tubular member axially slidably arranged inside the            outer tubular member; and        -   a resection element configured to resect tissue extending            through the tissue resection window,    -    wherein the inner and outer tubular member are arranged to        establish:        -   a first fluid flow channel suitable for transporting            resected tissue away from an area adjacent to the resection            element;        -   at least one second fluid flow channel suitable for            regulating a pressure in the distal portion and/or            configured to assist the first fluid flow channel in            transporting resected tissue.    -   2. The tissue cutting device according to any of the preceding        items, further comprising a pressure sensor.    -   3. The tissue cutting device according to any of the preceding        items, further comprising an actuator for controlling a sliding        movement of the resection element along the outer tubular member        to resect tissue extending through the resection window.    -   4. The tissue cutting device according to any of the preceding        items, wherein the at least one pressure sensor is in connection        with the first fluid flow channel.    -   5. The tissue cutting device according to any of the preceding        items, wherein the at least one pressure sensor is configured to        measure a pressure inside the outer tubular member in a region        adjacent to the tissue resection window.    -   6. The tissue cutting device according to any of the preceding        items, further comprising a vacuum generator in connection with        the first fluid flow channel.    -   7. The tissue cutting device according to any of the preceding        items, further comprising processing means configured to        determine whether the measured pressure is below a predetermined        pressure threshold.    -   8. The tissue cutting device according to item 7, wherein the        processing means is configured to determine whether the tissue        to be resected fills the resection window when vacuum is applied        in the first fluid flow channel based on the measured pressure.    -   9. The tissue cutting device according to any of items 7-8,        wherein the processing means is configured to determine whether        the measured pressure is below a predetermined pressure        threshold for longer than a predefine period of time when vacuum        is applied in the first fluid flow channel based on the measured        pressure.    -   10. The tissue cutting device according to any of the preceding        items, further comprising an inner tubular member.    -   11. The tissue cutting device according to item 10, wherein the        inner tubular member is axially slidably arranged inside the        outer tubular.    -   12. The tissue cutting device according to any of the preceding        items, wherein the resection element is configured to cut tissue        backwards towards a direction from the distal portion towards        the proximal portion.    -   13. The tissue cutting device according to any of the preceding        items, wherein the resection element is located distally to the        resection window when the resection window is open.    -   14. The tissue cutting device according to any of the preceding        items, further comprising a plunger sealingly engaged inside the        outer tubular member.    -   15. The tissue cutting device according to item 14, wherein the        plunger is an integral part of the resection element.    -   16. The tissue cutting device according to any of items 14-15,        further comprising a resection element control channel        incorporated into the sidewall of the outer tubular member,        wherein the resection element control channel is fluid        connection with a closed chamber defined by the outer tubular        member and the plunger.    -   17. The tissue cutting device according to item 16, wherein the        system is configured to control a fluid in the closed chamber        such that when a chamber pressure in the chamber is increased a        backwards movement of the resection element is produced and when        the chamber pressure is decreased a forwards movement of the        resection element is produced.    -   18. The tissue cutting device according to any of the preceding        items, further comprising a guidewire channel incorporated into        the sidewall of the outer tubular member.    -   19. The tissue cutting device according to according to item 18,        further comprising a guidewire arranged inside the guidewire        channel extending from a proximal end of the outer tubal member        to a distal end of the outer tubular member.    -   20. The tissue cutting device according to any of the preceding        items, further comprising a flexible catheter connected to the        outer tubular member and a control device.    -   21. The tissue cutting device according to item 20, wherein the        control device is configured to control the resection element        and/or the vacuum generator and/or application of the vacuum        generator and/or application of fluid into the second fluid flow        channel.    -   22. The tissue cutting device according to any of the preceding        items, further comprising a flex channel incorporated into the        sidewall of the outer tubular member.    -   23. The tissue cutting device according to any of the preceding        items, wherein the control device is configured to control a        flex wire in the flex channel.    -   24. The tissue cutting device according to any of the preceding        items, wherein resected tissue is aspirated from the area        adjacent to the resection element through the first fluid flow        channel.    -   25. The tissue cutting device according to any of the preceding        claims, wherein the resection window is located proximate to a        closed distal end of the outer tubular member, such as less than        0.1 mm, or less than 0.2 mm, or less than 0.3 mm, or less than        0.4 mm, or less than 0.5 mm, or less than 1.0 mm, or less than        2.0 mm, or less than 3.0 mm, or less than 4.0 mm, or less than        5.0 mm, or less than 10 mm, or less than 15 mm, or less than 20        mm, or less than 25 mm, or less than 30 mm.    -   26. The tissue cutting device according to any of the preceding        items, wherein the resection window has a length of less than 3        mm, or less than 4 mm, or less than 5 mm, or less than 6 mm, or        less than 7 mm, or less than 8 mm, or less than 9 mm, or less        than 10 mm, or less than 15 mm, or less than 20 mm, or less than        25 mm, or less than 30 mm, or less than 50 mm.    -   27. The tissue cutting device according to any of the preceding        items, wherein the resection window extends over a portion of a        circumference of the outer tubular member, such as less than 5%        of the circumference, or less than 6% of the circumference, or        less than 7% of the circumference, or less than 8% of the        circumference, or less than 9% of the circumference, or less        than 10% of the circumference, or less than 15% of the        circumference, or less than 20% of the circumference, or less        than 30% of the circumference, or less than 40% of the        circumference, or less than 50% of the circumference, or less        than 60% of the circumference.    -   28. The tissue cutting device according to any of the preceding        items, said resection window having an edge sloping downwards        towards the center of the resection window.    -   29. The tissue cutting device according to any of the preceding        items, wherein the resection element is an integrated part of        the inner tubular member.    -   30. The tissue cutting device according to any of the preceding        items, the inner tubular member having a hollow interior        defining the first fluid flow channel extending from an open        proximal end of the inner tubular member to an open distal end        of the inner tubular member, said open distal end comprising a        cutting surface defining an acute angle to the longitudinal axis        of the inner tubular member, forming a substantially oval edge        of the inner tubular member.    -   31. The tissue cutting device according to any of the preceding        items, wherein the inner tubular member is a tissue penetrating        cannula, wherein the open distal end is sharp.    -   32. The tissue cutting device according to item 31, wherein the        acute angle is between 1° and 30°.    -   33. The tissue cutting device according to any of items 31-32,        wherein the cannula is a lancet cannula having a sharpened        front.    -   34. The tissue cutting device according to any of the preceding        items, wherein an upper side of the resection element is        configured to slide smoothly along the inside of the outer        tubular member, thereby cutting tissue extending through the        tissue resection window.    -   35. The tissue cutting device according to any of the preceding        items, wherein the open distal end comprises a scalpel or razor        blade.    -   36. The tissue cutting device according to any of the preceding        items, wherein the inner tubular member, including the resection        element, is made of one piece.    -   37. The tissue cutting device according to any of the preceding        items, wherein the at least one second fluid flow channel is a        space between the outer tubular member and the inner tubular        member.    -   38. The tissue cutting device according to any of the preceding        items, the at least one second fluid flow channel having the        shape of an annular tube.    -   39. The tissue cutting device according to any of the preceding        items, wherein the at least one second fluid flow channel is        located in the opposite side of a cross-section of the outer        tubular member in relation to the resection window.    -   40. The tissue cutting device according to any of the preceding        items, wherein the at least one second fluid flow channel is        incorporated into the sidewall of the outer tubular member.    -   41. The tissue cutting device according to any of the preceding        items, the cutting device having one or more additional fluid        flow channels.    -   42. The tissue cutting device according to any of the preceding        items, the cutting device having a device outer diameter between        2 mm and 20 mm, or between 2 mm and 15 mm, or between 2 mm and        10 mm, or between 5 mm and 10 mm, or between 5 mm and 15 mm,        such as 2 mm, or 3 mm, or 4 mm, or 5 mm, or 6 mm, or 7 mm, or 8        mm, or 9 mm, or 10 mm, or 11 mm, or 12 mm, or 13 mm, or 14 mm,        or 15 mm, or 16 mm, or 17 mm, or 18 mm, or 19 mm, or 20 mm.    -   43. The tissue cutting device according to any of the preceding        items, the inner tubular member having an inner tubular inner        diameter between 1 mm and 10 mm, or between 1 mm and 7 mm, or        between 1 mm and 5 mm, or between 1 mm and 3 mm, such as 1 mm,        or 2 mm, or 3 mm, or 4 mm, or 5 mm, or 6 mm, or 7 mm, or 8 mm,        or 9 mm, or 10 mm, or 12 mm, or 14 mm, or 16 mm, or 18 mm, or 19        mm.    -   44. The tissue cutting device according to any of the preceding        items, wherein the difference between an inner tubular outer        diameter of the inner tubular member and an outer tubular inner        diameter is less than 5 mm, or less than 4 mm, or less than 3        mm, or less than 2 mm, or less than 1 mm, or less than 0.5 mm,        or less than 0.4 mm, or less than 0.3 mm, or less than 0.2 mm,        or less than 0.1 mm.    -   45. The tissue cutting device according to any of the preceding        items, the device having a length of between 50 mm and 500 mm,        or between 50 mm and 400 mm, or between 100 mm and 300 mm, or        between 50 mm and 200 mm, or between 100 mm and 200 mm, or        greater than 200 mm.    -   46. The tissue cutting device according to any of the preceding        items, further comprising at least one additional tubular member        inside the inner tubular member or outside the outer tubular        member.    -   47. The tissue cutting device according to any of the preceding        items, wherein the tissue cutting device is made of a rigid        material, selected from the group of ceramics, ceramic        composites, metal, such as aluminium or steel, or plastics, such        as polycarbonate (PC) or polymethylmethacrylate (PMMA).    -   48. The tissue cutting device according to any of the preceding        items, wherein the closed distal end is rounded or substantially        pointed.    -   49. The tissue cutting device according to any of the preceding        items, wherein the first fluid flow channel is configured to be        connected to a vacuum source configured to establish a fluid        flow to aspirate resected tissue away from an area adjacent to        the resection element through the channel.    -   50. The tissue cutting device according to any of the preceding        items, wherein the first fluid flow channel is suitable for        transporting resected tissue away from the resection element.    -   51. The tissue cutting device according to any of the preceding        items, further comprising at least one pressure sensor.    -   52. The tissue cutting device according to item 51, wherein the        at least one pressure sensor is located in the distal portion or        the proximate portion of the outer tubular member, or in the        distal end or proximal end of the inner tubular member.    -   53. The tissue cutting device according to any of items 51-52,        wherein the at least one pressure sensor is located outside the        outer tubular member.    -   54. The tissue cutting device according to any of the preceding        items, wherein the at least one second fluid flow channel is        configured to uphold a pressure in the distal portion such that        the pressure is substantially equal to the pressure outside the        tissue cutting device when the resection window is open.    -   55. The tissue cutting device according to item 54, wherein the        pressure outside the tissue cutting device a measured in        real-time.    -   56. The tissue cutting device according to any of the preceding        items, wherein the at least one second fluid flow channel is        suitable for regulating a pressure in the distal portion such        that material does not flow between an outer area of the device        and an inner area when the resection window is open.    -   57. The tissue cutting device according to any of the preceding        items, wherein the at least one second fluid flow channel        contains a liquid, such as water, or a saline solution, or a        glucose solution, to regulate the pressure.    -   58. The tissue cutting device according to any of the preceding        items, wherein the at least one second fluid flow channel is        configured to be connected to a pressure regulator.    -   59. The tissue cutting device according to any of the preceding        items, wherein the at least one second fluid flow channel is        configured to assist the first fluid flow channel in        transporting resected tissue away from the resection element        through the first fluid flow channel when the resection window        is closed.    -   60. The tissue cutting device according to any of the preceding        items, wherein the at least one second fluid flow channel is        configured to flush resected tissue away from the distal portion        through the first fluid flow channel, wherein the pressure        regulator is configured to generate a flow of liquid through the        at least one second fluid flow channel towards the distal        portion, the flow of liquid continuing from the distal portion        away from the distal portion through the first fluid flow        channel.    -   61. The tissue cutting device according to any of the preceding        items, wherein a primary channel of the at least one second        fluid flow channels is suitable for regulating a pressure in the        distal portion, and a secondary channel of the at least one        second fluid flow channels is configured to flush resected        tissue away from the distal portion through the first fluid flow        channel.    -   62. The tissue cutting device according to any of the preceding        items, wherein the cutting device is surgical instrument        configured to resect tissue of a heart.    -   63. The tissue cutting device according to any of the preceding        items, wherein the cutting device is surgical instrument        configured to resect tissue of a human and/or animal tissue.    -   64. The tissue cutting device according to any of the preceding        items, wherein the cutting device is configured to resect the        hypertrophic septum of a heart.    -   65. The tissue cutting device according to any of the preceding        items, wherein the cutting device is configured to be inserted        through the apex of a heart.    -   66. The tissue cutting device according to any of the preceding        items, wherein the cutting device is configured to be inserted        through the vasculature of the body, such as the femoral artery,        ascending aorta, subclavian artery or any other great vessel of        the body.    -   67. The tissue cutting device according to any of the preceding        items, further comprising a flexible section attached to the        device, said flexible section configured to pass through any        great vessel of the body.    -   68. The tissue cutting device according to any of the preceding        items, further comprising a guidewire configured to guide the        tissue cutting device to a position inside the body.    -   69. The tissue cutting device according to any of the preceding        items, further comprising an introducer configured to introduce        the tissue cutting device into any part or organ of the body,        such as the heart.    -   70. The tissue cutting device according to any of the preceding        items, further comprising one or more transmitter(s) and/or        transducer(s) configured to indicate the location of the tissue        cutting device.    -   71. The tissue cutting device according to item 70, wherein the        transmitter(s)/transducer(s) is/are ultrasonic        transmitter(s)/transducer(s).    -   72. The tissue cutting device according to any of items 70-71,        wherein the transmitter(s)/transducer(s) is/are located at the        closed distal end of the outer tubular member.    -   73. A method for resecting tissue using the tissue cutting        device according to any of items 1-65, comprising the steps:        -   opening the tissue resection window and during and after the            opening regulating the pressure in the distal portion            through the at least one second fluid flow channel such that            the pressure is substantially equal to the pressure outside            the tissue cutting device;        -   activate a vacuum generator connected to the first fluid            flow channel such that tissue located outside the cutting            device is aspirated into the distal portion of the outer            tubular member through the tissue resection window;        -   closing the tissue resection window by sliding the inner            tubular member in an axial direction lengthwise of the outer            tubular member towards the closed distal end, the resection            element thereby resecting tissue extending through the            tissue resection window;        -   increasing the pressure in the outer channel to generate a            flow of liquid through the outer channel towards the distal            portion, the flow of liquid continuing from the distal            portion away from the distal portion through the first fluid            flow channel.    -   74. The method according to item 73, wherein the liquid is        water, or a saline solution, or a glucose solution.    -   75. The method according to any of items 73-74, wherein the        vacuum generator is configured to generate a secondary        (negative) pressure or partial or complete vacuum in the inner        tubular member and distal portion, without delay, and wherein        the secondary pressure is decreased rapidly.    -   76. The method according to any of items 73-75, wherein the        steps of the method are repeated to resect several pieces of        tissue.    -   77. The method according to any of items 73-76, wherein the        tissue cutting device is assisted by transoesophageal or        transthoracic echocardiography of the heart and/or fluoroscopy.    -   78. A method for resecting the hypertrophic septum of a heart        according to the method of items 73-77.    -   79. A tissue removal device comprising the tissue cutting device        according to any of items 1-65, the tissue removal device        further comprising:        -   a vacuum generator;        -   a collector for collecting the resected tissue;        -   an actuator for controlling a sliding movement of the inner            tubular member along the outer tubular member;        -   a housing.    -   80. The tissue removal device according to item 79, further        comprising a regulating system for regulating the pressure in        the distal portion and regulating the secondary pressure in the        first tubular member and distal portion controlled by the vacuum        generator.    -   81. The tissue removal device according to any of items 79-80,        further comprising a lever mechanism configured for pushing the        inner tubular member in an axial direction lengthwise of the        outer tubular member towards the closed distal end, wherein the        lever is connected to the actuator.

1. A tissue cutting system for cutting tissue of a heart, such as tissueof a septum of a heart, comprising: an outer tubular member having aproximal portion and a distal portion, said distal portion comprising atissue resection window; a resection element axially slidably arrangedinside the outer tubular member configured to resect tissue extendingthrough the tissue resection window; at least one pressure sensor;wherein the outer tubular member and resection element are arranged toestablish: a first fluid flow channel suitable for transporting resectedtissue away from an area adjacent to the resection element; and at leastone second fluid flow channel configured to assist the first fluid flowchannel in transporting resected tissue.
 2. The tissue cutting systemaccording to claim 1, further comprising an actuator for controlling asliding movement of the resection element along the outer tubular memberto resect tissue extending through the resection window.
 3. The tissuecutting system according to claim 1, wherein the at least one pressuresensor is in connection with the first fluid flow channel.
 4. The tissuecutting system according to claim 1, wherein the at least one pressuresensor is configured to measure a pressure inside the outer tubularmember in a region adjacent to the tissue resection window.
 5. Thetissue cutting system according to claim 1, further comprising a vacuumgenerator in connection with the first fluid flow channel.
 6. The tissuecutting system according to claim 1, further comprising a processorconfigured to determine whether the measured pressure is below apredetermined pressure threshold.
 7. The tissue cutting system accordingto claim 6, wherein the processor is configured to determine whether thetissue to be resected fills the resection window when vacuum is appliedin the first fluid flow channel based on the measured pressure.
 8. Thetissue cutting system according to claim 6, wherein the processor isconfigured to determine whether the measured pressure is below apredetermined pressure threshold for longer than a predefine period oftime when vacuum is applied in the first fluid flow channel based on themeasured pressure.
 9. The tissue cutting system according to claim 1,further comprising an inner tubular member.
 10. The tissue cuttingsystem according to claim 9, wherein the inner tubular member is axiallyslidably arranged inside the outer tubular.
 11. The tissue cuttingsystem according to claim 1, wherein the resection element is configuredto cut tissue backwards towards a direction from the distal portiontowards the proximal portion.
 12. The tissue cutting system according toclaim 1, wherein the resection element is located distally to theresection window when the resection window is open.
 13. The tissuecutting system according to claim 1, further comprising a plungersealingly engaged inside the outer tubular member.
 14. The tissuecutting system according to claim 13, wherein the plunger is an integralpart of the resection element.
 15. The tissue cutting system accordingto claim 13, further comprising a resection element control channelincorporated into the sidewall of the outer tubular member, wherein theresection element control channel is fluid connection with a closedchamber defined by the outer tubular member and the plunger.
 16. Thetissue cutting system according to claim 1, wherein the system isconfigured to control a fluid in the closed chamber such that when achamber pressure in the chamber is increased a backwards movement of theresection element is produced and when the chamber pressure is decreaseda forwards movement of the resection element is produced.
 17. The tissuecutting system according to claim 1, further comprising a guidewirechannel incorporated into the sidewall of the outer tubular member. 18.The tissue cutting system according to according to claim 17, furthercomprising a guidewire arranged inside the guidewire channel extendingfrom a proximal end of the outer tubal member to a distal end of theouter tubular member.
 19. The tissue cutting system according to claim1, further comprising a flexible catheter connected to the outer tubularmember and a control device.
 20. The tissue cutting system according toclaim 19, wherein the control device is configured to control theresection element and/or the vacuum generator and/or application of thevacuum generator and/or application of fluid into the second fluid flowchannel.
 21. The tissue cutting system according to claim 1, furthercomprising a flex channel incorporated into the sidewall of the outertubular member.
 22. The tissue cutting system according to claim 1,wherein the control device is configured to control a flex wire in theflex channel.
 23. The tissue cutting system according to claim 1,wherein resected tissue is aspirated from the area adjacent to theresection element through the first fluid flow channel.
 24. The tissuecutting system according to claim 1, wherein the resection element is anintegrated part of the inner tubular member.
 25. The tissue cuttingsystem according to claim 1, wherein an upper side of the resectionelement is configured to slide smoothly along the inside of the outertubular member, thereby cutting tissue extending through the tissueresection window.
 26. The tissue cutting system according to claim 1,wherein the at least one second fluid flow channel is a space betweenthe outer tubular member and the inner tubular member.
 27. The tissuecutting system according to claim 1, wherein the cutting device has adevice outer diameter between 2 mm and 20 mm, or between 2 mm and 15 mm,or between 2 mm and 10 mm, or between 5 mm and 10 mm, or between 5 mmand 15 mm, or 2 mm, or 3 mm, or 4 mm, or 5 mm, or 6 mm, or 7 mm, or 8mm, or 9 mm, or 10 mm, or 11 mm, or 12 mm, or 13 mm, or 14 mm, or 15 mm,or 16 mm, or 17 mm, or 18 mm, or 19 mm, or 20 mm.
 28. The tissue cuttingsystem according to claim 1, wherein the at least one second fluid flowchannel is configured to uphold a pressure in the distal portion suchthat the pressure is substantially equal to the pressure outside thetissue cutting device when the resection window is open.
 29. The tissuecutting system according to claim 1, wherein the at least one secondfluid flow channel is configured to be connected to a pressureregulator, and wherein the at least one second fluid flow channel isconfigured to flush resected tissue away from the distal portion throughthe first fluid flow channel, wherein the pressure regulator isconfigured to generate a flow of liquid through the at least one secondfluid flow channel towards the distal portion, the flow of liquidcontinuing from the distal portion away from the distal portion throughthe first fluid flow channel.
 30. The tissue cutting system according toclaim 1, further comprising a collector for collecting the resectedtissue.
 31. The tissue cutting system according to claim 1, furthercomprising a housing.
 32. A method for resecting tissue using the tissuecutting system according to claim 1, comprising the steps: positioningthe resection window adjacent to tissue to cut; generating a vacuumpressure; connecting the vacuum pressure to the first fluid flowchannel, thereby aspirating tissue through the resection window;measuring and analysing the pressure in the first fluid channel for apredefined period of time; and if the measured period remains below apredefined pressure threshold for longer than a predefine period oftime, sliding the resection element thereby cutting tissue, otherwisedisconnecting the vacuum pressure to the first fluid flow channel.